| Term | Definition / Meaning / Stand for |
| ADB |
Abdominal |
| AB |
Abduction |
| AH |
Acetohydroxy Acid |
| ASA |
Acetylsalicylic Acid |
| AID |
Acquired Immune Deficiency |
| AIM |
Acute Ischemic Myocardial Injury |
| AIS |
Acute Ischemic Stroke |
| AMI |
Acute Myocardial Infarction |
| ARR |
Acute Respiratory Rate |
| ATO |
Acute Tonic Clonic |
| ATA |
Acute Tubular Necrosis |
| AVE |
Acute Vertebrobasilar Event |
| ATP |
Adenosine Triphosphate |
| ATC |
Adrenal Cortical Tumor |
| ABC |
Airway, Breathing, Circulation |
| AGS |
Alagille Syndrome |
| AEA |
Alveolar Epithelial Cells |
| AD |
Alzheimer's Disease |
| ACNS |
American College of Neurology and Surgery |
| AMP |
Amino Acid Metabolism |
| AL |
Amyotrophic Lateral Sclerosis |
| ASL |
Amyotrophic Lateral Sclerosis |
| AIS |
Androgen Insensitivity Syndrome |
| AGD |
Anorectal Growth Disorder |
| ACG |
Anterior Cingulate Gyrus |
| AEA |
Anterior Ethmoidal Artery |
| AG |
Anterior Gyrus |
| ATF |
Anterior Talofibular Ligament |
| ATU |
Antigen-Tolerant Uterus |
| ANA |
Antinuclear Antibody |
| APA |
Antiphospholipid Antibody |
| APS |
Antiphospholipid Syndrome |
| ATD |
Antithyroid Drugs |
| AO |
Aortic Origin |
| AVA |
Aortic Valve Area |
| A-Z |
Arachnoid-Zygomaticus (Used for muscle descriptions) |
| AIOL |
Artificial Intraocular Lens |
| ASP |
Aspartate Aminotransferase |
| AIR |
Aspiration Injury Risk |
| ATR |
Atrial Rate |
| AT |
Atrial Tachycardia |
| AVB |
Atrioventricular Block |
| AVC |
Atrioventricular Conduction |
| AV |
Atrioventricular |
| AUM |
Auditory Unit Membrane |
| AUD |
Auditory |
| ADNS |
Autonomic Dysfunction Syndrome |
| AR |
Autonomic Reflex |
| ADS |
Autosomal Dominant Syndrome |
| AxD |
Axial Dyskinesia |
| Aorta |
Main artery that carries oxygenated blood |
| AbdB |
Abdominal-B |
| ACh |
Acetylcholine |
| ASCL |
Achaete-scute Like |
| AIDS |
Acquired Immunodeficiency Syndrome |
| ARIS |
Acrosome Reaction-Inducing Substance |
| ADL |
Activities of Daily Living |
| AFM |
Acute Flaccid Myelitis |
| AIDP |
Acute Inflammatory Demyelinating Polyneuropathy |
| AIN |
Acute Interstitial Nephritis |
| AML |
Acute Myeloid Leukemia |
| APL |
Acute Promyelocytic Leukemia |
| APE |
Acute Pulmonary Edema |
| ARF |
Acute Renal Failure |
| APC |
Adenomatous Polyposis Coli |
| ACTH |
Adrenocorticotropic Hormone |
| ALD |
Adrenoleukodystrophy |
| AHN |
Adult Hippocampal Neurogenesis |
| ADR |
Adverse Drug Reaction |
| ALT |
Alanine Aminotransferase |